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3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 556 · 40 questions
TalentJR

How to do it in your head (Hundreds first): Keep the first number as it is and split the second into hundreds, tens and ones. Add (or take away) the hundreds first, then the tens. Finish with the ones — bridge through a ten if you need to.

NameDateTime takenScore ___ / 40
  1. 1.526 − 156 =
  2. 2.574 − 314 =
  3. 3.617 + 356 =
  4. 4.507 − 149 =
  5. 5.570 − 206 =
  6. 6.739 − 514 =
  7. 7.135 + 306 =
  8. 8.581 − 456 =
  9. 9.669 + 398 =
  10. 10.520 + 458 =
  11. 11.378 + 482 =
  12. 12.625 + 606 =
  13. 13.713 + 334 =
  14. 14.142 + 246 =
  15. 15.447 + 661 =
  16. 16.347 + 266 =
  17. 17.869 − 471 =
  18. 18.958 − 278 =
  19. 19.636 + 687 =
  20. 20.624 + 484 =
  21. 21.874 − 773 =
  22. 22.889 − 402 =
  23. 23.614 + 229 =
  24. 24.963 − 318 =
  25. 25.220 + 401 =
  26. 26.491 + 444 =
  27. 27.978 − 141 =
  28. 28.581 − 471 =
  29. 29.869 − 369 =
  30. 30.284 + 232 =
  31. 31.887 − 449 =
  32. 32.898 − 425 =
  33. 33.286 + 543 =
  34. 34.883 − 431 =
  35. 35.856 − 284 =
  36. 36.733 + 281 =
  37. 37.281 + 528 =
  38. 38.487 − 201 =
  39. 39.324 + 294 =
  40. 40.226 + 654 =

Answer key

  1. 370
  2. 260
  3. 973
  4. 358
  5. 364
  6. 225
  7. 441
  8. 125
  9. 1067
  10. 978
  11. 860
  12. 1231
  13. 1047
  14. 388
  15. 1108
  16. 613
  17. 398
  18. 680
  19. 1323
  20. 1108
  21. 101
  22. 487
  23. 843
  24. 645
  25. 621
  26. 935
  27. 837
  28. 110
  29. 500
  30. 516
  31. 438
  32. 473
  33. 829
  34. 452
  35. 572
  36. 1014
  37. 809
  38. 286
  39. 618
  40. 880

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